Yeah idk about Rome 2, never played that one. It sounds like the game is unbalanced if an all-swordsman army is best and nobody has come up with a counter. Then again I doubt any of those games are very well balanced for pvp battles.
And every community had their own...
WH 3 basically solved this issue by making MP battles be capture the points style - genuinely, it freed us from having to make house rules.